Many of the kings were wicked in God's sight, and didn't do much, if anything, to bring the nation back to God. Some were righteous, though. But the one thing that particularly stood out to me was the use of the high places of false worship, which were often built by the kings who turned their hearts from the one true God. The wicked kings blatantly built and used these areas of false worship. Yet sometimes when a righteous king reigned, the places were destroyed and the people turned back to God. However, there were a few kings who followed the Lord, but not fully, and many times this was because they did not destroy the places of false worship.
Jotham was one of these. "And he did what was right in the eyes of the Lord...except he did not enter the temple of the Lord. But the people still followed corrupt practices." (2 Chronicles 27:2) Manassah was another, for while the people served the God, they used the high places of false worship to sacrifice to the Lord. Both these men allowed the influence of pagan people and nations to corrupt their worship towards God, and because they permitted some sin in their lives, the Israelites did not follow God wholeheartedly. Their intended to follow God (though Manassah didn't until later in his reign), but this sin distracted them and their people from restoring complete fellowship with God.
It's was also interesting to see that after many wicked or weak rulers, there came a godly king who completely destroyed all the false places of sacrifices and worship, called the people to repentance, and celebrated the Passover. After Jotham, Ahaz led the people into further wickedness, building more high places and leading the people in false worship. But after Ahaz, came Hezekiah. Amon reigned after Manassah, and he, too, served false gods, and refused to humble himself before God. But after Amon, came Josiah.
Hezekiah and Josiah were the two kings who sought after God. They weren't perfect, but they turned Judah's heart to repent and seek God. They purged the land of false images and places of worship. They both restored and ordered the holy Temple, and they both celebrated the Passover once again. They refused to allow the pagan influence to corrupt the land, and by doing so they preserved the nation--the line from which Christ would come--for yet a little longer.
Perhaps this can be a lesson to us, too. When we allow sinful influences, thoughts, and action to creep into our lives, it slowly draws us away from God. Sometimes it isn't noticeable at first, but it takes conscious action to destroy the false strongholds of our hearts and to restore our relationship with God. If we're going to allow just that "one little thing" to plant seeds in our mind that turn us from God, then it's going to weaken our appetite for spiritual things. We need to guard the purity of our hearts and minds if we desire to follow after Christ. Single-hearted devotion to Christ and unity with fellow believers requires that we lay aside sin and live in obedience--for that brings blessing.
And the king stood in his place and made a covenant before the Lord, to walk after the Lord and to keep his commandments and his testimonies and his statues, with all his heart and all his soul, to perform the words of the covenant that were written in this book.
Then he made all who were present in Jerusalem and in Benjamin join in it. And the inhabitants of Jerusalem did according to the covenant of God, the God of their fathers.
And Josiah took away all the abominations from all the territory that belonged to the people of Israel and made all who were present in Israel serve the Lord their God. All his days they did not turn away from following the Lord, the God of their fathers.
2 Chronicles 34:31-33